SOA Question

cbriant

Hi,

I have come across the following question:

The network contains one primary internal DNS server called INTERNAL and one external DNS server called EXTERNAL which is connected to the Internet. Several secondary servers exist on the network, the number of additions is low.

You monitor the secondary server and notice the number of SOA requests is high. You must minimize the bandwith used for SOA requests.

The correct answers were:

Increase the refresh intervall.

Configure the notify list on DNSExt


I can understand the refresh interval, but why would configuring the notify list have any effect?

dynamik

DNS Notify on Technet

Scroll to the bottom, it's the last section.

It looks like using dns notify will notify the other servers of changes, so they don't query the server to see if any changes have been made. I'm still learning this as well, so maybe someone more experienced can confirm and/or elaborate.

cbriant

I guess it's the "you monitor the secondary server" implies that the external server is not notifying all the secondaries of changes. Is this the clue to choosing the second option?

dynamik

The way I understand it is that the secondary servers are going to poll external server every so often to see if the SOA has changed. Using DNS notify will have the external server send notifications to the other servers saying that there is an update, which will eliminate the SOA requests from the secondary servers. Again, I don't have a firm grasp on this material yet, so if someone else wants to chime in, it would be appreciated.